Japanese Defense Minister Yasukazu Hamada and his Chinese counterpart Li Shangfu are expected to hold talks on the sidelines of a regional security meeting in Singapore in early June, a source close to bilateral relations said Monday.

The plan comes as Japanese Prime Minister Fumio Kishida and other Group of Seven leaders affirmed the importance of dialogue with China in their summit in Hiroshima through Sunday.

Japanese Defense Minister Yasukazu Hamada (L) and his Chinese counterpart Li Shangfu. (Kyodo)

At the planned meeting, the first of its kind since June last year, Hamada is likely to express concerns about repeated intrusions by Chinese coast guard vessels into Japanese territorial waters, and joint naval exercises by Beijing and Moscow conducted around Japan, the source said.

Chinese coast guard vessels have repeatedly been spotted around the Senkaku Islands in the East China Sea. The uninhabited islets are controlled by Tokyo but claimed by Beijing, which calls them Diaoyu.

Hamada may also convey the importance of preserving peace and stability across the Taiwan Strait, the source said.

The defense ministers are likely to meet on the occasion of the annual Asia Security Conference, known as Shangri-La Dialogue, scheduled for June 2-4 in the Southeast Asian island city-state.

In the communique released after their three-day summit, the G-7 leaders said they "stand prepared to build constructive and stable relations with China."

The leaders called on China to resolve conflicts related to Taiwan in a peaceful manner. Beijing regards the self-ruled democratic island as a renegade province to be unified with the mainland, by force if necessary.

On Monday, Kishida stressed that Tokyo and Beijing must make efforts to build "constructive and stable" bilateral ties, adding he will consider holding talks with Chinese President Xi Jinping from such a point of view.

Bilateral relations have deteriorated after a senior employee of Japanese pharmaceutical company Astellas Pharma Inc. was detained by China in March on suspicion of engaging in espionage.

In Singapore, Hamada and Li are also expected to confirm the proper operation of a hotline between their defense authorities, and talk about how to respond to North Korea, which has been stepping up its nuclear and missile development programs, according to the source.

Tokyo and Beijing are arranging a high-level economic dialogue involving their foreign and economic ministers in Japan this year, which marks the 45th anniversary of the signing of the China-Japan Treaty of Peace and Friendship, the source added.